Upload file with new name in server (loopback/nodejs)

I am trying to upload a file in loopback server. It is being uploaded successfully. All the properties of file are read-only, but i want value of name property to be updated (with new value) before save. These are the property of file when opened.

Following is a function to which I am sending array of all opened files to be saved (after opening all the files).

fileUpload.post = function (files) {
  for (var i = 0; i < files.length; i++) {
    if (angular.isDefined(files[i])) {
      files[i].upload = Upload.upload({
        url: "http://localhost:3000/api/Containers/files/upload",
        data: {
          file: files[i]
        }
      });
    }
  }
}

In server models folder, I have a model called container. Trying to work with beforeRemote function in container.js. But don't know what to write inside it. I think i should write something inside it to change value of name property.

What should I do?

module.exports = function (Container) {
var fs = require('fs');
  Container.beforeRemote('upload', function(context, user, next) {

  });
  Container.afterRemote('upload', function(context,user,next) {

  });
};

via Umair Jameel